Heat limited running pace

In hot conditions, your maximum running pace is limited by your ability to cool off. It is possible to calculate your theoretical maximum running pace at a particular temperature and humidity given your height and weight. This calculator is based on my Running Heat Model.

Contents

1 Introduction

When you run, you produce heat that must be removed from your body. In cold conditions, this is not a problem, but as the temperature and humidity go up, it becomes harder to remove the generated heat. If you generate more heat than you lose, your core temperature will rise and you will have to slow down. For most people, the rise in core temperature causes a gradual, though unpleasant, slow down. However, extreme dedication can force some people to push hard enough to raise their core temperature enough to cause collapse, coma and even death.

2 Heat limited pace table

The table below shows an example set of maximum running paces for someone who is 174cm/70inches high and weighs 60Kg/132lbs. You can create a customized version of this table by filling in the form below

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

50f/(10c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

55f/(12.8c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

60f/(15.6c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

65f/(18.3c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

70f/(21.1c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

4:25

75f/(23.9c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

4:24

5:01

5:47

80f/(26.7c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

4:07

4:48

5:39

6:48

8:21

85f/(29.4c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

4:44

6:33

9:34

>14:00

>14:00

90f/(32.2c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

5:37

8:36

>14:00

>14:00

>14:00

95f/(35c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

4:28

7:02

12:40

>14:00

>14:00

>14:00

100f/(37.8c)

Unlimited

Unlimited

Unlimited

Unlimited

Unlimited

5:16

9:40

>14:00

>14:00

>14:00

>14:00

3 Input Form

Height

Weight

Temperature Units

Temperature Increment

4 Heat Acclimation Training

Heat Acclimation can improve your ability to keep cool by sweating more and sweating earlier, as well as making your sweat more dilute. Heat adaptation can also teach you the warning signs of an elevated core temperature so you can adjust your pace or take action to cool off before things get dangerous. However, heat adaptation does not change the limits of physics, nor does it allow you to tolerate a higher core temperature.

5 Important caveats

In addition to the caveats in Running Heat Model, the calculations of maximum pace make extra assumptions. This means that the pace indicated may not be safe.